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101.
Ryota Nakahar Kazuma Sekiguchi Kenichiro Nonak Masahiro Takasugi Hiroki Hasebe Kenichi Matsubara 《控制理论与应用(英文版)》2022,20(2):248-262
When heavy-duty commercial vehicles (HDCVs) must engage in emergency braking, uncertain conditions such as the brake
pressure and road profile variations will inevitably affect braking control. To minimize these uncertainties, we propose a
combined longitudinal and lateral controller method based on stochastic model predictive control (SMPC) that is achieved via
Chebyshev–Cantelli inequality. In our method, SMPC calculates braking control inputs based on a finite time prediction that
is achieved by solving stochastic programming elements, including chance constraints. To accomplish this, SMPC explicitly
describes the probabilistic uncertainties to be used when designing a robust control strategy. The main contribution of this
paper is the proposal of a braking control formulation that is robust against probabilistic friction circle uncertainty effects.
More specifically, the use of Chebyshev–Cantelli inequality suppresses road profile influences, which have characteristics
that are different from the Gaussian distribution, thereby improving both braking robustness and control performance against
statistical disturbances.Additionally, since theKalman filtering (KF) algorithm is used to obtain the expectation and covariance
used for calculating deterministic transformed chance constraints, the SMPC is reformulated as a KF embedded deterministic
MPC. Herein, the effectiveness of our proposed method is verified via a MATLAB/Simulink and TruckSim co-simulation. 相似文献
102.
The micro-nanoformability of Pt-based metallic glass and the nanoforming of three-dimensional structures 总被引:1,自引:0,他引:1
Yasunori Saotome Kenichi Imai Shigeo Shioda Susumu Shimizu Tao Zhang Akihisa Inoue 《Intermetallics》2002,10(11-12)
Pt48.75Pd9.75Cu19.5P22 amorphous alloy exhibits obvious glass transition behavior at a temperature of Tg=502 K, which is below the crystallization temperature Tx=588 K, and develops a supercooled liquid state in a wide temperature range of ΔTx (=Tx−Tg)=86 K. The present paper investigates the macroscopic and microscopic deformation behavior of the material and the possibility of micro-nano forming as a fabrication method and material for nano-devices. On a macroscopic scale, the material exhibits a Newtonian viscous flow in a supercooled liquid state. An index of the microformability is also evaluated by the geometrical transferability of a die shape to the material. For this study, we fabricated V-grooved micro dies of (100) Si by a silicon process. The V-groove dies are from 100 nm to 1 μm wide. The material exhibits superior formability on micrometer and nanometer scales and may possibly be applied to micro-nanomaterials for micro-nano devices. 相似文献
103.
Motomichi Koyama Michael Rohwerder Cemal Cem Tasan Asif Bashir Eiji Akiyama Kenichi Takai 《Materials Science & Technology》2017,33(13):1481-1496
ABSTRACTThis paper gives an overview of recent progress in microstructure-specific hydrogen mapping techniques. The challenging nature of mapping hydrogen with high spatial resolution, i.e. at the scale of finest microstructural features, led to the development of various methodologies: thermal desorption spectrometry, silver decoration, the hydrogen microprint technique, secondary ion mass spectroscopy, atom probe tomography, neutron radiography, and the scanning Kelvin probe. These techniques have different characteristics regarding spatial and temporal resolution associated with microstructure-sensitive hydrogen detection. Employing these techniques in a site-specific manner together with other microstructure probing methods enables multi-scale, quantitative, three-dimensional, high spatial, and kinetic resolution hydrogen mapping, depending on the specific multi-probe approaches used. Here, we present a brief overview of the specific characteristics of each method and the progress resulting from their combined application to the field of hydrogen embrittlement.This paper is part of a thematic issue on Hydrogen in Metallic Alloys 相似文献
104.
This paper investigates a distributed optimal energy consumption control strategy under mean-field game based speed consensus. Large scale vehicles in a traffic flow is targeted instead of individual vehicles, and it is assumed that the propulsion power of vehicles is hybrid electric powertrain. The control scheme is designed in the following two stages. In the first stage, in order to achieve speed consensus, the acceleration control law is designed by applying the MFG (mean-field game) theory. In the second stage, optimal powertrain control for minimizing energy consumption is obtained through coordinate the engine and the motor under the acceleration constraint. The simulation is conducted to demonstrate the effectiveness of the proposed control strategy. 相似文献
105.
Koji Takahashi Kenichi Uchiide Yoshitaka Kimura Wataru Nakao Kotoji Ando Masahiro Yokouchi 《Journal of the American Ceramic Society》2007,90(7):2159-2164
A mullite/SiC whisker/SiC particle multi-composite, having excellent crack-healing ability and mechanical properties, was hot pressed in order to investigate the crack-healing behavior under stress and the resultant fatigue strength at the temperature of healing. A semi-elliptical surface crack 100 μm in surface length was introduced on each specimen. The pre-cracked specimens were crack healed under cyclic or constant stress by using a three-point bending stress at 1473 K, and the resultant bending strength and cyclic fatigue strength were measured at 1473 K. The pre-crack on the surface of the specimens could be healed even under stress. The threshold stresses for crack healing, as determined by evaluating the strengths of crack-healed specimens at a healing temperature of 1473 K, were 170 MPa for both constant and cyclic stresses, corresponding to 77% of the bending strength of the pre-cracked specimens. The static and cyclic fatigue behaviors of crack-healed specimens were also investigated at a healing temperature of 1473 K. 相似文献
106.
Fukuyama Y Yasuda N Kim J Murayama H Ohshima T Tanaka Y Kimura S Kamioka H Moritomo Y Toriumi K Tanaka H Kato K Ishikawa T Takata M 《The Review of scientific instruments》2008,79(4):045107
An ultra-high-precision clock system for long time delay has been developed for picosecond time-resolved x-ray diffraction measurements using synchrotron radiation (SR) pulses and synchronized femtosecond laser pulses. The time delay control between pump laser pulse and the probe SR pulse was achieved by combining an in-phase quadrature modulator and a synchronous counter. This method allowed us to change the delay time by a nearly infinite amount while maintaining the precision of +/-8.40 ps. Time-resolved diffraction measurements using the delay control system were demonstrated for precise measurement of an acoustic velocity in a single crystal of gallium arsenide. 相似文献
107.
Vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) has been applied to the detection of volatile organic compounds (VOCs), including aromatic, chlorinated, and oxygenated compounds. Photoionization mass spectra of 23 VOCs were measured using SPI-TOFMS at 10.5 eV (118 nm). The limits of detection of VOCs using SPI-TOFMS at 10.5 eV were estimated to be a few ppbv. The mass spectra of 20 VOCs exhibit only the parent ion and its isotopes' signals. The ionization processes of the VOCs were discussed on the basis of the reaction enthalpies predicted by the quantum chemical calculations. Absolute photoionization cross-sections for 23 VOCs, including 12 newly measured VOCs, at 10.5 eV were determined in comparison to the reported absolute photoionization cross-section of NO. 相似文献
108.
Effect of collagen fibril formation on bioresorbability of hydroxyapatite/collagen composites 总被引:2,自引:0,他引:2
Yunoki S Marukawa E Ikoma T Sotome S Fan H Zhang X Shinomiya K Tanaka J 《Journal of materials science. Materials in medicine》2007,18(11):2179-2183
Porous hydroxyapatite/collagen (HAp/Col) composite is a promising biomaterial and a scaffold for bone tissue engineering.
The effect of fibril formation of Col in the porous composite on bioresorbability and mechanical strength was investigated.
The fibril formation, in mixing a self-organized HAp/Col nanocomposite and sodium phosphate buffer at a neutral condition,
occurred during incubation at 37 °C, resulting in gelation of the mixture. The porous composites with and without the incubation
were obtained by freeze-drying technique, in which macroscopic open pores were formed. The compressive strength of the porous
composite with the incubation (34.1 ± 1.6 kPa) was significantly higher than that without the incubation (28.0 ± 3.3 kPa)
due to the fibril formation of Col. The implantations of the porous composites treated with a dehydrothermal treatment in
bone holes revealed that bioresorption was clearly depended on the fibril formation. The bioresorbability in vivo was almost
matched to the in vitro test using enzymatic reaction of collagenase. 相似文献
109.
110.